The present invention relates to an image processing system and data modulation/demodulation method thereof and, more particularly, to an image processing system which compresses an input image data to an audio signal level and then transfers the data through conventional telephone lines after reproducing the image data stored in a memory. Such a system also makes it possible to compress or reconstruct the image data without loss.
Generally, in the image processing system such as a video tape recorder (VTR), the image data are sorted in a magnetic recording media, and played back again if desired. However, there is a problem in that in order to play back the stored image data, a drum is always required, since tapes and disks are usually used as the magnetic recording media. Further, the image data are extended over a high frequency band and they are impossible to transfer. Therefore, a frequency band of 108 Hz is required for digital image processing and the capacity of a memory must be very large.
Conversely, a recording wavelength .lambda. is the ratio of a tape velocity .upsilon. to a frequency f. That is, .lambda.=.upsilon./f. In order to record the image signal of a high frequency band, rotary-head drums which are able to play back the recorded signal beyond the predetermined wavelength .lambda. by increasing a relative velocity have been proposed, but these drums have some limitations in minimizing the size of the video tape recorder.